I have two tables. One is a log table; another contains, essentially, coupon codes that can only be used once.
The user needs to be able to redeem a coupon, which will insert a row into the log table ...

Recent versions of MySQL (using InnoDB) support many alter table queries without exclusive locking the table.
Does PostgreSQL support this to any level? That is, can I add/drop columns from a table ...

I want to execute two transactions concurrently in pgAdmin:
--The first transaction should modify the age of Paul
BEGIN;
DECLARE newage INTEGER;
--the original age of Paul is 32
newage := Select age ...

Postgresql 9.4 allows to REFRESH materialized views CONCURRENTLY, if they have a UNIQUE index.
I am looking fo a SQL-query that lists all materialized views that DO NOT have such a UNIQUE or PRIMARY ...

I tried to find an answer in Kalen Delaney's SQL Server Concurrency but there is no mention of metadata.
The problem is how to ensure that only one of these reads and index creates executes from one ...

I have created an SSIS package for downloading file from FTP server. When I debug the package, everything goes fine. But when I shedule the package as Job step, it sometimes fails to connect. The job ...

I have an InnoDB table with an index on it. I have a few million rows to insert, so I thought I might take advantage of the row-level locking and do it in parallel. I'm inserting in batches of 10000, ...

Let's assume you have a task FOO that can be queued once every minute, and a pool of 50 workers that can be paused. The queue is paused for 10 minutes, and 10 FOO tasks are queued. When the queue is ...

For a short period in time we had a concurrency issue that lead to subsequent faults in our application (Java, Spring, Hibernate).
Since we are using dictionary managed tablespaces, I first thought ...

I want to build a function which will insert an email if the email value doesn't exist in the table and return the email_id of the row. How can I do this?
Also how can I return the id if the email was ...

I was reading the MongoDB documentation, where it says about read uncommit: MongoDB allows clients to read documents inserted or modified before it commits these modifications to disk, regardless of ...

I am using a postgres DB to implement a scheduling of jobs for a large number of computers/processes. To make the story short, every job has its id, all scheduling is implemented with three tabes: all ...

If I need to update same row with two concurrent thread then is it possible in SQL Server?
Suppose I have one table that contains Id and Name columns and now I want to update the third number Id with ...

AFAIK running transactions as READ UNCOMMITTED means that there is no lock, so every change caused by a transaction is immediately visible to other transactions.
Is it correct to assume that this is ...

I am using a timestamp column called updated_at for cache invalidation. More information on this particular technique here.
The queries all have the same format
UPDATE "managers" SET "updated_at" = ...

I am trying to write a stored procedure that will take new values from a temp table, merge them into an actual table, giving me the ids of the inserted rows, and the rows that already exist matching ...

I have a postgres database which contains details on clusters of servers, such as server status (active, standby, etc). Active servers at any time may need to fail over to a standby, and I don't care ...

I read that I can have different isolation levels per connection and in the server.
The default isolation level is REPEATABLE-READ.
So if I have a transaction that issues a SERIALIZED to the client ...

I'm writing a Java application to update a relational database (currently H2, but we'll likely switch to PostgreSQL at some point). I have a process which does the following:
Poll an external system ...

We're maintaining a POS/WMS Application built in powerbuilder that runs on SQL Server 2008 R2 backend. Recently, we've been having a lot of locking issues and I believe it has to do with how we handle ...

We've had issues, during high concurrency, of queries returning non-sensical results - results the violate the logic of the queries being issued. It took a while to reproduce the issue. I've managed ...